Thermal Reactions of Benzene

Mead, Frank C.; Burk, Robert E.

doi:10.1021/ie50303a013

Cited by 11 publications

(8 citation statements)

References 3 publications

(3 reference statements)

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“…6,7 Many studies 4,8 have reported that the high temperature chemistry of benzene has a significant impact on the formation of larger PAHs and soot but unfortunately until now its own pyrolysis mechanism has not been clarified. [9][10][11][12][13][14][15][16][17][18][19] The identification of gas phase products of benzene pyrolysis is limited even though many studies have been carried out in shock tube 1,17,[19][20][21][22] and flow systems. 14,23 The well known mechanism for the growth of PAHs is the HACA.…”

Section: Introductionmentioning

confidence: 99%

A highly efficient growth mechanism of polycyclic aromatic hydrocarbons

Shukla

Koshi

2010

Phys. Chem. Chem. Phys.

110

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A highly efficient growth mechanism of polycyclic aromatic hydrocarbons (PAHs) initiated and accelerated by phenyl radicals has been investigated on the basis of kinetic analysis of gas phase reaction products of pyrolysis of benzene with and without addition of acetylene and acetylene only. Pyrolytic reactions were performed in a flow tube reactor and the resulting products were detected by an in situ direct sampling mass spectrometric technique using a vacuum ultraviolet (VUV) single photon ionization (SPI) time of flight mass spectrometry (TOFMS). The detected species varies from smaller to larger PAHs up to m/z = 454 (C(36)H(22)) including primary PAHs, polyphenyl-PAHs and cyclopentafused-PAHs (CP-PAHs). The peculiarity of this result is an appearance of mass peaks at regular mass number intervals of approximately 76 that correspond to phenyl-PAHs produced by phenyl radical addition (+C(6)H(5), +77) followed by hydrogen elimination (-H, -1). All such mass peaks were found diminishing with appearance of -2 mass number peaks with increasing temperatures, certainly due to a conversion of thermally rather unstable phenyl-PAHs into stable condensed PAHs through a dehydrocyclization (-H(2), -2) process. In the same way, in the case of only acetylene pyrolysis, mass peaks at regular mass number intervals of 24 corresponding to the HACA (hydrogen abstraction/C(2)H(2) addition) products, were observed. Kinetic analysis of formation pathways of those observed products showed the active role of PAC (phenyl addition/cyclization) because of its efficiency to continue the endless growth of PAHs, while the HACA was only found efficient for producing symmetrical PAHs by filling a triple fusing site (four carbon bay structure). Especially, acetylene was mixed with benzene to understand the impact of HACA on the PAC path ways that resulted in enhancement of phenyl-PAHs production in spite of trapping of active and chain carrier species phenyl radicals by C(2)H(2) to form phenylacetylene. The comparison of HACA and PAC concluded that PAC is a highly efficient mechanism for the growth of PAHs and lastly their combined roles in combustion have been discussed. Hopefully, PAC will be useful to understand the process of aromatic growth, from furnaces to stellar atmospheres.

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Section: Introductionmentioning

confidence: 99%

A highly efficient growth mechanism of polycyclic aromatic hydrocarbons

Shukla

Koshi

2010

Phys. Chem. Chem. Phys.

110

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“…In line with previous work on hydrocarbons, [14][15][16][17] experiments have been performed in a jet stirred reactor which was operated at temperatures between 873 and 973 K, residence times between 1 and 4 s, at a pressure of 106 kPa and at high dilution. Conversions ranging from 0.04 to 22.6% have been obtained. The attention has been paid to the analysis of the products of the reaction.…”

Section: Introductionmentioning

confidence: 92%

Thermal Decomposition of Norbornane (bicyclo[2.2.1]heptane) Dissolved in Benzene: Experimental Study and Mechanism Investigation

et al. 2007

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The thermal decomposition of norbornane (dissolved in benzene) has been studied in a jet stirred reactor at temperatures between 873 and 973 K, at residence times ranging from 1 to 4 s and at atmospheric pressure, leading to conversions from 0.04 to 22.6%. 25 reaction products were identified and quantified by gas chromatography, amongst which the main ones are hydrogen, ethylene and 1,3-cyclopentadiene.A mechanism investigation of the thermal decomposition of the norbornane -benzene binary mixture has been performed. Reactions involved in the mechanism have been reviewed: unimolecular initiations 1 by C-C bond scission of norbornane, fate of the generated diradicals, reactions of transfer and propagation of norbornyl radicals, reactions of benzene and cross-coupling reactions.

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“…As the simplest aromatic hydrocarbon, benzene has provided the point of departure for innumerable studies, theoretical and experimental, of molecular properties and reactions. It should likewise provide the starting point in a systematic understanding of thermal decompositions involving aromatics, and, indeed, it has been studied from time to time, e.g., in connection with formation of surface carbon de-posits1-3 or with soot formation in diffusion flames.1 234•5 Kinetic studies have been carried out by Mead and Burk, 6 Kinney and DelBel,7 Kinney and Slysh,8 910and most recently by Bauer and Aten.9 Attempts to obtain rate constants were made mainly by the first and last of these. Slysh8 did obtain a rate constant, but only at one temperature (1473°K.).…”

Section: Introductionmentioning

confidence: 99%